Different SORT based on data entry

I have a macro in a workbook that looks like this:

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I want to amend that code so that the SORT performed in the macro is only performed when data is entered into a particular cell.

Until that point...I want the SORT to sort by Range("AG7"), and then by Range("C7)...excluding Range("AH7") from the sort.

For example:

Say cell A1 is empty.
I want the macro to sort by Range("AG7") descending, and then by Range("C7") ascending...until data is entered into cell A1.

After data is entered into cell A1, I want the macro to include Range("AH7") in the sort.

So, basically, I need the macro to look in cell A1 and see if it's blank before sorting, to determine which sortation to perform.